ELECTRIC MOTOR VEHICLE AND METHOD FOR CONTROLLING THE MOTOR VEHICLE

Description

Technical field of the invention

[0001] The present invention relates to the field of electrically powered vehicles, such as pure electric vehicles and hybrid vehicles.

[0002] The invention also relates to a method for piloting such electrically powered vehicles. State of the art

[0003] An electric vehicle is, generally speaking, a vehicle with a powertrain that includes an electric motor coupled to the vehicle's drive wheels. This electric motor (also called a power electric motor) is configured to transmit mechanical torque to the drive wheels to propel the vehicle.

[0004] Generally, such a transmission is achieved via a gearbox comprising one or more reduction elements allowing the engine to transmit sufficient torque to the drive wheels, particularly during acceleration or starting phases.

[0005] Thus, in existing electric vehicles, it is common to use a constant power reduction gear to multiply the torque transmitted by the electric motor to the drive wheels. For example, some vehicles are equipped with a main gearbox with a reduction ratio of 1 / 10, which, during certain specific operating phases, allows the mechanical torque transmitted to the drive wheels to be multiplied by 10.

[0006] However, while these arrangements provide sufficient torque to the drive wheels for starting and acceleration, they require the electric motor to operate at a high rotational speed. Thus, a paradox of electric vehicle operation is that they consume more energy on highways than in cities. Consequently, the driving range of electric vehicles is reduced, even though the electric motor could be adapted to power the drive wheels without an exponential increase in the electrical energy it supplies.EP3517346 A1 and FR2847015 A1 also disclose electric / hybrid powered vehicle respectively; comprising: drive wheels; a powertrain including at least one electric power motor and a power transmission mechanism between said power motor and the drive wheels, the power transmission mechanism comprising a main reducer / a main reducer having an epicyclic gear train architecture respectively; interposed between the power motor and the drive wheels; according to the art of technology. Object of the invention

[0007] The present invention aims to provide a solution that addresses all or part of the aforementioned problems.

[0008] This goal is achieved through the implementation of an electric vehicle, comprising: drive wheels; a powertrain including at least one electric power motor and a power transmission mechanism between said power motor and the drive wheels, the power transmission mechanism comprising a main reduction gear interposed between the power motor and the drive wheels, said main reduction gear having an epicyclic gear train architecture with at least one stage, where each stage comprises: ∘ a planet carrier; ∘ a central planetary shaft centered about a reduction rotation axis; ∘ a peripheral planetary shaft externally surrounding the central planetary shaft, and being coaxial with the central planetary shaft about the reduction rotation axis; ∘ at least one planet gear, disposed between the central planetary shaft and the peripheral planetary shaft, meshing with the central planetary shaft and the peripheral planetary shaft,and being configured to rotate around the reduction rotation axis; an accelerator pedal; a control mechanism separate from the powertrain, the control mechanism comprising: an electric control motor; an irreversible reduction mechanism interposed between the control motor and the power transmission mechanism, and acting on the power transmission mechanism in such a way as to adjust, according to the rotational speed of the control motor, the reduction ratio of the main reducer, to modulate a rotational speed of the power motor in order to adjust the value of the mechanical torque transmitted by the power transmission mechanism to the drive wheels,the irreversible reduction mechanism preventing the transmission of mechanical forces from the regulating motor to the drive wheels and preventing the transmission of mechanical forces from the power transmission mechanism to the regulating motor, said irreversible reduction mechanism being a worm gear system in which the worm is rotationally coupled to an output shaft of the regulating motor and the wheel is rotationally coupled to the planet carrier of at least one stage of said main reducer, a rotation of the wheel causing said planet carrier to rotate in a direction enabling an increase in the overall reduction ratio of the power transmission mechanism; an electronic control unit ensuring control of the power motor and the regulating motor according to control laws stored in a memory of the electronic control unit,said control laws being at least dependent on an action on the accelerator pedal of the electric vehicle.

[0009] The previously described provisions allow for the design of an electric vehicle in which an irreversible reduction mechanism is used to control the torque of the power motor. The irreversible nature of this reduction mechanism allows for the mechanical isolation of the control motor from the powertrain, ensuring that no power delivered by the power motor is transmitted to the control motor, and vice versa.

[0010] The electric vehicle may also have one or more of the following characteristics, taken alone or in combination.

[0011] According to one embodiment, the regulating motor includes an output shaft, said output shaft being rotationally fixed to an element of the irreversible reducing mechanism.

[0012] According to one embodiment, the electrically powered vehicle includes at least one electrical energy storage system configured to supply electrical energy to at least one electric motor selected from the powertrain motor and the control motor.

[0013] In one embodiment, the main gearbox has an overall reduction ratio of 0.25 between an input mechanically connected to an output of the power motor and an output mechanically connected to the drive wheels. In another embodiment, the main gearbox comprises a single stage, said stage having a reduction ratio of 0.25.

[0014] According to one embodiment, the main reducer of the power transmission mechanism comprises at least two stages mounted in series.

[0015] According to one embodiment, the main reducer includes reversing free gears arranged between each stage.

[0016] According to one embodiment, each floor has a reduction rate, said reduction rate of each floor being chosen so that an overall reduction rate of the main reducer is between 1 / 3 and 1 / 5.

[0017] According to one embodiment, the main reducer comprises three stages mounted in series where each stage has a reduction ratio of 0.63, so that the main reducer has an overall reduction ratio of 0.25.

[0018] According to one embodiment, the wheel of the worm gear system is rotationally fixed to the planet carrier of one stage of at least one stage of the main reducer.

[0019] According to one embodiment, the worm gear of the worm wheel system is rotationally fixed to the output shaft of the regulating motor.

[0020] According to one embodiment, the electrically powered vehicle includes a first gear and a second gear arranged between the wheel of the worm gear system and the planet carrier of one of the stages of the main reducer, said first and second gears being meshed with each other, the first gear being further meshed with the wheel of the worm gear system, and the second gear being rotationally fixed to the planet carrier.

[0021] According to one embodiment, said first and second gears are mounted in series between the wheel of the worm gear system and a planet carrier of one of the stages of the reducer.

[0022] According to one embodiment, the worm gear system is configured to have a reduction ratio between 1 / 8 and 1 / 12.

[0023] According to one embodiment, the reduction ratio of the worm gear system is equal to 1 / 10.

[0024] According to one embodiment, the worm screw comprises a thread having a thread angle less than or equal to 6°, and in particular substantially equal to 6°.

[0025] Thus, the worm gear system is considered irreversible, as the rotation of the wheel attached to the planet carrier is dependent on the rotation of the worm gear. This worm gear is configured to disengage, at the speed of the regulating motor, from the force exerted by the worm gear system. Consequently, an increase in the speed of the regulating motor results in an increase in the torque delivered to the drive wheels by the power motor.

[0026] In one embodiment, the worm gear and the wheel of the worm gear system are made of steel. For example, the contact surfaces between the wheel and the worm gear of the worm gear system are made of lubricated steel.

[0027] Thus, and advantageously, the effort induced on the worm is compensated by the dynamic friction effort between the worm and the wheel, because the coefficient of friction of steel on steel is approximately equal to the sine of the thread angle.

[0028] The objective of the invention is also achieved through the implementation of a method for controlling an electric vehicle, to control an electric vehicle according to one of the embodiments described above, the control method being implemented by the control unit and comprising: a command reception phase by the control unit, in which a command dependent on the actuation of the accelerator pedal of the electric motor vehicle is received, said command being representative of an absolute value of a depressment of the accelerator pedal;in the event that the absolute value of the accelerator pedal depressment is strictly greater than an absolute threshold depressment value, implementation of a regulation phase including a step of rotating the regulation motor so as to adjust, according to the rotation speed of the regulation motor, the reduction ratio of the main reducer, to modulate the rotation speed of the power motor in order to adjust the value of the mechanical torque transmitted by the power transmission mechanism to the drive wheels, a direction of rotation of the regulation motor then causing the worm of the worm wheel system to rotate in a direction allowing said worm to give way to a mechanical force of the wheel on the worm;In all other cases, a speed modulation phase is implemented, in which a value of the current supplied by the power motor is modulated proportionally to the absolute value of the accelerator pedal depressed, so as to modulate the torque transmitted by the power motor to the drive wheels.

[0029] The provisions described above allow us to propose a method for controlling an electric vehicle in which a regulation phase is implemented to adjust the transmission of mechanical torque to the vehicle's drive wheels according to the absolute value of the accelerator pedal deflection. Indeed, increasing the rotational speed of the regulation motor implies an increase in the torque delivered to the drive wheels by the power motor.

[0030] The piloting process may also have one or more of the following characteristics, taken alone or in combination.

[0031] According to one embodiment, the absolute threshold depress value is equal to 50% of a total depressed stroke of the accelerator pedal.

[0032] According to one embodiment, the modulation phase is implemented so that the current value supplied by the power motor is modulated proportionally to the absolute value of the accelerator pedal depressed between a zero current value and a maximum nominal current value corresponding to a maximum value that can be supplied by the power motor.

[0033] It is therefore well understood that when the absolute value of the accelerator pedal depressment is between 0% and the absolute threshold depressment value, the torque supplied by the power motor is modulated according to the absolute value of the accelerator pedal depressment between zero torque and a nominal value of the power motor torque.

[0034] According to one embodiment, during the regulation phase, the power motor supplies a current whose value is equal to the maximum nominal current value.

[0035] It is therefore well understood that when the absolute value of the accelerator pedal depressment is strictly greater than the absolute threshold depressment value, the torque supplied by the power motor is equal to the power motor's nominal torque value, and the rotational speed of the regulating motor is modulated between 0 and a nominal rotational speed value for the regulating motor. For example, the nominal rotational speed value of the regulating motor is equal to 6000 rpm.

[0036] Thus, the rotation of the regulating motor makes it possible to induce an increase in the torque transmitted by the power motor to the drive wheels, via the main reducer.

[0037] According to one embodiment, the wheel of the worm gear system limits the rotation of the satellite carrier to a speed dependent on the rotation speed of the regulating motor.

[0038] According to one embodiment, the control laws stored in the memory of the control unit include all or part of the steps of the control process as described above. Brief description of the drawings

[0039] Other aspects, objectives, advantages, and features of the invention will become clearer upon reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the accompanying drawings in which: [ Fig. 1 ] There figure 1 is a schematic view of the electric vehicle according to a first embodiment. Fig. 2 ] There figure 2 is a schematic view of the electric vehicle according to a second embodiment. Fig. 3 ] There figure 3 is a schematic view of the regulation mechanism according to one embodiment. Fig. 4 ] There figure 4is a schematic view of the control process according to one embodiment. Fig. 5 ] There figure 5 is a schematic view of the evolution of the torque supplied to the drive wheels as a function of the rotational speed of the power motor of a state-of-the-art electric vehicle. Fig. 6 ] There figure 6 is a schematic view of certain steps in the piloting process according to one embodiment. Fig. 7 ] There figure 7 is a schematic view of certain steps in the piloting process according to one embodiment. Detailed description

[0040] In the figures and throughout the description, the same reference numerals represent identical or similar elements. Furthermore, the various elements are not drawn to scale to ensure clarity. Moreover, the different embodiments and variants are not mutually exclusive and can be combined.

[0041] As illustrated on the figures 1 and 2The invention relates to an electric vehicle 1, comprising in particular drive wheels 3, and a powertrain 10 including at least one electric motor 11. Generally, such an electric vehicle 1 includes at least one electrical energy storage system 7, such as a battery, which is configured to supply electrical energy to the electric motor 11. The electric motor 11 is configured to drive the drive wheels 3 in rotation, in order to enable the electric vehicle 1 to move forward.

[0042] For this purpose, the electrically powered vehicle includes a power transmission mechanism 20 interposed between said power motor 11 and the drive wheels 3. This power transmission mechanism 20 includes a main reduction gear 21 interposed between the power motor 11 and the drive wheels 3. According to the embodiments shown in the figures 1 and 2The main reducer 21 of the power transmission mechanism 20 has an epicyclic gear train architecture with at least one stage, where each stage comprises: a planet carrier 22; a central planetary shaft 23 centered about a reduction rotation axis X; a peripheral planetary shaft 24 externally surrounding the central planetary shaft 23, and being coaxial with the central planetary shaft 23 about the reduction rotation axis X; at least one planet gear 25, disposed between the central planetary shaft 23 and the peripheral planetary shaft 24, meshing with the central planetary shaft 23 and the peripheral planetary shaft 24, and being configured to rotate about the reduction rotation axis X.

[0043] Some state-of-the-art electric vehicles 1 feature a main gearbox with a reduction ratio of 1 / 10. This is advantageous for situations requiring high acceleration, but detrimental for constant-speed travel at high speeds. Therefore, it can be envisaged that the main gearbox 21 of the electric vehicle 1 will have an overall reduction ratio of 0.25 between an input mechanically connected to an output of the power motor 11 and an output mechanically connected to the drive wheels 3. According to the variant shown in the figure 2 The main reducer 21 comprises a single stage, said stage having a reduction ratio of 0.25. Alternatively, and as shown in the figure 1The main gearbox 21 of the power transmission mechanism 20 may comprise at least two stages connected in series, and in particular three stages connected in series. If the main gearbox 21 comprises several stages, each stage may be provided with a reduction ratio chosen so that the overall reduction ratio of the main gearbox 21 is between 1 / 3 and 1 / 5. Thus, if the main gearbox 21 comprises three stages connected in series, each stage may advantageously have a reduction ratio of 0.63, so that the main gearbox 21 has an overall reduction ratio of 0.25. The articulation of the different stages of the main gearbox may be implemented by means of reversing free-spinning gears 26 arranged between each stage.

[0044] The electric vehicle 1 further comprises a control mechanism 30 separate from the powertrain 10, which includes an irreversible reduction mechanism 33 and an electric control motor 31. Advantageously, this electric control motor 31 can be powered by an electrical energy storage system 7 identical or different from the one that powers the power motor 11. The control motor 31 may include an output shaft 32 rotatably fixed to an element of the irreversible reduction mechanism 33.

[0045] The irreversible reduction mechanism 33 is interposed between the control motor 31 and the power transmission mechanism 20, and acts on the power transmission mechanism 20 in such a way as to adjust, according to the rotational speed of the control motor 31, the reduction ratio of the main gearbox 21, thereby modulating the rotational speed of the power motor 11 in order to adjust the value of the mechanical torque transmitted by the power transmission mechanism 20 to the drive wheels 3. The irreversible reduction mechanism 33 prevents the transmission of mechanical forces from the control motor 31 to the drive wheels 3 and prevents the transmission of mechanical forces from the power transmission mechanism 20 to the control motor 31. Thus, the irreversible reduction mechanism ensures perfect power separation between the power unit 10 and the control mechanism 30.

[0046] As illustrated on the figures 1 and 2 , and more specifically on the figure 3The irreversible reduction mechanism 33 comprises a worm gear system in which the worm 35 is rotationally coupled to the output shaft 32 of the control motor 31. For example, the worm 35 of the worm gear system is rotationally fixed to the output shaft 32 of the control motor 31. The wheel 34, for its part, is rotationally coupled to a planet carrier 22 of one stage of the main gearbox 21. Thus, a rotation of the wheel 34 causes the planet carrier 22 to rotate in a direction that increases the overall reduction ratio of the power transmission mechanism 20. To achieve this, the wheel 34 of the worm gear system can be rotationally fixed to the planet carrier 22 of at least one stage of the main gearbox 21. The worm gear system is configured to have a reduction ratio between 1 / 8 and 1 / 12, and in particular a reduction rate equal to 1 / 10.

[0047] The irreversibility of the worm gear system can be guaranteed by the choice of parameters and materials for the worm 35 and the wheel 34. For example, the worm 35 may have a thread with a thread angle 36 of 6° or less, and in particular, substantially 6°. Furthermore, the worm 35 and the wheel 34 of the worm gear system may be made of steel. More specifically, the contact surfaces between the wheel 34 and the worm 35 of the worm gear system may be made of lubricated steel. Advantageously, the force induced on the worm 35 is compensated by the dynamic friction between the worm 35 and the wheel 34, since the coefficient of friction of steel on steel is substantially equal to the sine of the thread angle 36.As a result, the worm gear system is considered irreversible, the rotation of the wheel 34, which is fixed to the planet carrier 22, being dependent on the rotation of the worm gear 35. It is therefore possible that the worm gear 35 is configured to disengage, at the rotational speed of the regulating motor 31, from the force exerted by the wheel 34 of the worm gear system, thus performing regulation by modifying the reduction ratio of the main gearbox 21. Thus, an increase in the speed of the regulating motor 31 implies an increase in the torque delivered to the drive wheels 3 by the power motor 11.

[0048] According to the embodiment shown in the figure 2The electrically powered vehicle 1 comprises a first gear 14 and a second gear 16 arranged between the wheel 34 of the worm gear system and a planet carrier 22 of one of the stages of the main gearbox 21. The first and second gears 14 and 16 are meshed with each other; the first gear 14 is also meshed with the wheel 34 of the worm gear system, and the second gear 16 is rotationally fixed to the planet carrier 22. For example, said first and second gears 14 and 16 are mounted in series between the wheel 34 of the worm gear system and a planet carrier 22 of one of the stages of the gearbox. This embodiment advantageously reduces the number of stages of the main gearbox 21, requiring only one stage. For example, it may be provided that the first gear 14 is two or three times smaller than the second gear 16, or vice versa.

[0049] Finally, the electric vehicle 1 includes an electronic control unit 50 that controls the power motor 11 and the regulating motor 31 according to control laws stored in a memory 51 of the electronic control unit 50. These control laws are at least dependent on an action on an accelerator pedal of the electric vehicle 1.

[0050] The provisions described above make it possible to propose an electric motorized vehicle 1 in which an irreversible reduction mechanism 33 is used to control the torque of the power motor 11. The irreversible nature of the irreversible reduction mechanism 33 makes it possible to mechanically isolate the regulating motor 31 from the powertrain 10 so that no power delivered by the power motor 11 is transmitted to the regulating motor 31 and vice versa.

[0051] The invention also relates to a method for piloting an electrically powered vehicle 1, one embodiment of which is shown in the figures 4 to 6 This control method allows for the control of an electric motor vehicle 1 of the type described above, and is implemented by the control unit 50. In particular, it may be provided that the control laws stored in the memory 51 of the control unit 50 include all or part of the steps of the control method described below.

[0052] The control process first comprises a command reception phase P1 by the control unit 50, in which a command dependent on the actuation of an accelerator pedal of the electric motorized vehicle 1 is received. This command represents an absolute value of the accelerator pedal depressment Vc.

[0053] In the case where the absolute value of the accelerator pedal depressment Vc is strictly greater than an absolute threshold depressment value Vs, the control method includes the implementation of a regulation phase P3 comprising a rotation step E3 of the regulation motor 31 so as to adjust, according to the rotation speed of the regulation motor 31, the reduction ratio of the main reducer 21, to modulate the rotation speed of the power motor 11 in order to adjust the value of the mechanical torque transmitted by the power transmission mechanism 20 to the drive wheels 3.More specifically, if the electric vehicle 1 includes an irreversible reduction mechanism 33 comprising a worm gear system, during the regulation phase P3, a direction of rotation of the control motor 31 drives the worm gear 35 of the worm gear system in a direction that allows the worm gear 35 to yield to a mechanical force exerted by the wheel 34 on the worm. It is therefore understood that the wheel 34 of the worm gear system limits the rotation of the planet carrier 22 to a speed dependent on the rotational speed Va of the control motor 31. In other words, the irreversible reduction mechanism 33 reduces the reduction ratio of the main gearbox 11 to implement the regulation phase P3.

[0054] There Figures 5 to 7illustrate a comparison between a method for piloting an electric motor vehicle (1) according to the prior art, and an embodiment of the piloting method according to the invention. figure 5 This illustrates, in particular, the evolution of the torque transmitted by the power motor 11 to the drive wheels 3 by a prior art electric vehicle 1. This prior art electric vehicle 11 may, for example, have a main reduction gear 21 with a reduction ratio of 1 / 10. Advantageously, such a system allows the speed of the electric vehicle 1 to increase proportionally to the rotational speed of the power motor 11 up to approximately 85 km / h. However, beyond this speed, the torque transmitted to the drive wheels 3 decreases, leading to high electrical consumption of the power motor 11.

[0055] An embodiment of the piloting method according to the invention is shown in the figures 6 And 7 In particular, the Figure 6B illustrates the accelerator pedal depressed travel between 0% of the total accelerator pedal depressed travel and 100% of said total accelerator pedal depressed travel. According to this embodiment, the absolute threshold depressed value Vs is equal to 50% of the total accelerator pedal depressed travel. Therefore, when the absolute value of the accelerator pedal depressed travel Vc is strictly greater than 50%, the regulation phase P3 is implemented, leading to an increase in the torque transmitted to the drive wheels 3, as illustrated in Figure 6A, and 7Advantageously, during the regulation phase P3, the power motor 11 supplies a current equal to a maximum rated current value, corresponding to the maximum current that the power motor 11 can supply. It is therefore understood that when the absolute value of the accelerator pedal depressment Vc is strictly greater than the absolute threshold depressment value Vs, the torque supplied by the power motor 11 is equal to the rated torque value of the power motor, and the rotational speed of the regulation motor 31 is modulated between 0 and a rated rotational speed value of the regulation motor. For example, the rated rotational speed value of the regulation motor is 6000 rpm.

[0056] In all other cases, the control method includes the implementation of a speed modulation phase P5, in which the current supplied by the power motor 11 is modulated proportionally to the absolute value of the accelerator pedal deflection Vc, so as to modulate the torque transmitted by the power motor 11 to the drive wheels 3. It is therefore understood that when the absolute value of the accelerator pedal deflection Vc is between 0% and the absolute threshold deflection value Vs, the torque supplied by the power motor 11 is modulated according to the absolute value of the accelerator pedal deflection Vc between zero torque and a nominal torque value of the power motor. Thus, the rotation of the control motor 31 makes it possible to induce an increase in the torque transmitted by the power motor 11 to the drive wheels 3, via the main gearbox 21.

[0057] For example, the modulation phase P5 is implemented so that the current value supplied by the power motor 11 is modulated proportionally to the absolute value of the accelerator pedal depressment Vc between a zero current value and the maximum nominal current value.

[0058] The provisions described above allow us to propose a method for controlling an electrically powered vehicle 1 in which a regulation phase P3 is implemented to adjust the transmission of mechanical torque to the drive wheels 3 of the vehicle according to the absolute value of the accelerator pedal depressment Vc. Indeed, increasing the rotational speed of the regulation motor 31 implies an increase in the torque delivered to the drive wheels 3 by the power motor 11.

Claims

1. An electrically powered vehicle (1), comprising: - drive wheels (3); - a powertrain (10) including at least one electric power motor (11) and a power transmission mechanism (20) between said power motor (11) and the drive wheels (3), the power transmission mechanism (20) comprising a main reducer (21) interposed between the power motor (11) and the drive wheels (3), said main reducer (21) having an epicyclic gear architecture with at least one stage, wherein each stage comprises: • a planet carrier (22); • a central planetary shaft (23) centered about a reduction rotation axis (X); • a peripheral planetary shaft (24) externally surrounding the central planetary shaft (23), and being coaxial with the central planetary shaft (23) about the reduction rotation axis (X); • at least one planet gear (25), arranged between the central planetary shaft (23) and the peripheral planetary shaft (24), meshing with the central planetary shaft (23) and the peripheral planetary shaft (24), and being configured to rotate about the reduction rotation axis (X); - an accelerator pedal; - a regulating mechanism (30) separate from the powertrain (10), the regulating mechanism (30) comprising: • an electric regulating motor (31); • an irreversible reducer mechanism (33) interposed between the regulating motor (31) and the power transmission mechanism (20), and acting on the power transmission mechanism (20) in such a way as to adjust, as a function of the rotational speed of the regulating motor (31), the reduction ratio of the main reducer (21), to modulate a rotational speed of the power motor (11) in order to adjust the value of the mechanical torque transmitted by the power transmission mechanism (20) to the drive wheels (3), the irreversible reducer mechanism (33) preventing transmission of mechanical forces from the regulating motor (31) to the drive wheels (3) and preventing transmission of mechanical forces from the power transmission mechanism (20) to the regulating motor (31), said irreversible reducer mechanism (33) being a wheel-and-worm system, the worm (35) of which is coupled in rotation with an output shaft (32) of the regulating motor (31), and the wheel (34) of which is coupled in rotation with the planet carrier (22) of one stage of said at least one stage of the main reducer (21), a rotation of the wheel (34) causing said planet carrier (22) to rotate in a direction allowing the overall reduction ratio of the power transmission mechanism (20) to be increased; - an electronic control unit (50) ensuring driving of the power motor (11) and the regulating motor (31) according to control laws stored in a memory (51) of the electronic control unit (50), said control laws being at least dependent on an action on the accelerator pedal of the electrically powered vehicle (1).

2. The electrically powered vehicle (1) according to claim 1, comprising at least one electrical energy storage system (7) configured to supply electrical energy to at least one electric motor selected from the power motor (11) of the powertrain (10) and the regulating motor (31).

3. The electrically powered vehicle (1) according to any one of claims 1 or 2, wherein the main reducer (21) of the power transmission mechanism (20) comprises at least two stages connected in series.

4. The electrically powered vehicle (1) according to any one of claims 1 to 3, wherein each stage has a reduction ratio, said reduction ratio of each stage being chosen so that an overall reduction ratio of the main reducer (21) is between 1 / 3 and 1 / 5.

5. The electrically powered vehicle (1) according to any one of claims 1 to 4, comprising a first gear (14) and a second gear (16) arranged between the wheel (34) of the worm-and-wheel system and the planet carrier (22) of one of the stages of the main reducer (21), said first and second gears (14, 16) being meshed with each other, the first gear (14) being further meshed with the wheel (34) of the worm-and-wheel system, and the second gear (16) being secured in rotation to the planet carrier (22).

6. The electrically powered vehicle (1) according to any one of claims 1 to 5, wherein the worm-and-wheel system is configured to have a reduction ratio of between 1 / 8 and 1 / 12.

7. The electrically powered vehicle (1) according to any one of claims 1 to 6, wherein the worm (35) comprises a thread having a thread angle (36) less than or equal to 6°, and in particular substantially equal to 6°.

8. An electrically powered vehicle (1) drive method for driving an electrically powered vehicle (1) according to any one of claims 1 to 7, the drive method being implemented by the control unit (50) and comprising: - a setpoint reception phase (P1) by the control unit (50), wherein a setpoint dependent on the actuation of the accelerator pedal of the electrically powered vehicle (1) is received, said setpoint being representative of an absolute value of an accelerator pedal depression (Vc); - in the event that the absolute value of the accelerator pedal depression (Vc) is strictly greater than a threshold depression absolute value (Vs), implementation of a regulation phase (P3) comprising a step of rotating (E3) the regulating motor (31) so as to adjust, as a function of the rotational speed of the regulating motor (31), the reduction ratio of the main reducer, to modulate the rotational speed of the power motor in order to adjust the value of the mechanical torque transmitted by the power transmission mechanism (20) to the drive wheels (3), a rotation direction of the regulating motor (31) then causing the worm (35) of the worm-and-wheel system to rotate in a direction enabling said worm (35) to yield to a mechanical force of the wheel (34) on the worm (35); - in all other cases, implementation of a power motor (20) rotation speed modulation phase (P5), wherein a value of the current provided by the power motor (11) is modulated proportionally to the absolute value of the accelerator pedal depression (Vc), so as to modulate the torque transmitted by the power motor (11) to the drive wheels (3).

9. The drive method according to claim 8, wherein the threshold depression absolute value (Vs) is equal to 50% of a total accelerator pedal depression stroke.

10. The drive method according to any one of claims 8 or 9, wherein the modulation phase (P5) is implemented so that the current value provided by the power motor (11) is modulated proportionally to the absolute value of the accelerator pedal depression (Vc) between a zero current value and a maximum rated current value corresponding to a maximum value capable of being provided by the power motor (11).

11. The drive method according to claim 10, wherein, during the regulation phase, the power motor (11) provides a current the value of which is equal to the maximum rated current value.